A gunman has opened fire in a gay nightclub in Colorado Springs, in the United States, killing five people and leaving 18 injured before a 22-year-old suspect was subdued by "heroic" patrons and arrested by police.
Two guns, including a "long rifle", were found at Club Q after the shooting on Saturday night, Police Chief Adrian Vasquez said.
Police identified the gunman as Anderson Lee Aldrich, who was in custody and being treated for injuries.
On its Facebook page, the club called it a "hate attack".
But Investigators were still determining a motive, and the attack was being investigated to see if it should be prosecuted as a hate crime, El Paso County District Attorney Michael Allen said.
Charges against the suspect "will likely include first-degree murder", he said.
Police identified the gunman as Anderson Lee Aldrich, who was in custody and being treated for injuries.
A man with the same name and age was arrested in 2021 after his mother reported he threatened her with "a homemade bomb, multiple weapons and ammunition", according to authorities.
Police did not confirm whether it was the same person, and said they were investigating whether the suspect had been arrested before.
'We were just enjoying ourselves'
Joshua Thurman said he was in the club with about two dozen other people and was dancing when the shots began.
He initially thought it was part of the music, until he heard another shot and said he saw the flash of a gun muzzle.
Mr Thurman, 34, said he ran with another person to a dressing room where someone already was hiding.
They locked the door, turned off the lights and got on the floor but could hear the violence unfolding, including the gunman getting beaten up, he added.
"I could have lost my life — over what? What was the purpose?" he said as tears ran down his cheeks.
"We were just enjoying ourselves. We weren't out harming anyone. We were in our space, our community, our home, enjoying ourselves like everybody else does."
'Heroic people' confronted the gunman
Authorities were called to Club Q at 11:57pm local time on Saturday with a report of a shooting, and the first officer arrived at midnight.
"At least two heroic people" confronted the gunman and stopped the shooting, Chief Vasquez said.
"We owe them a great debt of thanks."
"Club Q is a safe haven for our LGBTQ citizens," he said.
"I'm so terribly saddened and heartbroken."
Of the 25 injured, at least seven were in critical condition, authorities said. Some were hurt trying to flee, and it was unclear if all of the victims were shot, a police spokesperson said.
Images of the scene after the shooting showed security and emergency vehicles with flashing blinkers parked on a street near the venue.
By 4am local time, police had taped off the area around the club, which is located in a strip mall on the outskirts of Colorado Springs.
The FBI said it was providing assistance to the local police department who are leading the investigation into the incident.
Authorities said they were investigating whether the attack was motivated by hate.
'Devastated by senseless attack'
On its Facebook page, a statement from Club Q said it was "devastated by the senseless attack on our community".
"Our prays (sic) and thoughts are with all the victims and their families and friends," the statement continued.
"We thank the quick reactions of heroic customers that subdued the gunman and ended this hate attack."
Colorado Governor Jared Polis, who in 2018 became the first openly gay man in the country to be elected governor, said he had spoken to Colorado Springs Mayor John Suthers and offered every available state resource to local law enforcement.
"We are eternally grateful for the brave individuals who blocked the gunman, likely saving lives in the process, and for the first responders who responded swiftly to this horrific shooting," he said in a statement on social media.
"Colorado stands with our LGTBQ Community and everyone impacted by this tragedy as we mourn."
In its Google listing, Club Q describes itself as an "adult-oriented gay and lesbian nightclub hosting theme nights such as karaoke, drag shows & DJs".
At the time it was the worst mass shooting in recent US history.
That shooter had claimed allegiance to a leader of Islamic State. He was killed in an exchange of gunfire with police.
Colorado Springs is Colorado's second-most populous city, 113 kilometres south of the capital Denver.
Reuters/AP
